


Gemini

by Gement



Series: Batman: Millennials in Love [5]
Category: Batman - All Media Types
Genre: (no contact just voyeurism focused on shared partner), Bloodplay, Endurance Sex, Incest-adjacent, M/M, Masochism, Needles, Objectification, PWP, Top Batman, yo dawg I heard you like Batman
Language: English
Status: Completed
Published: 2020-10-04
Updated: 2020-10-04
Packaged: 2021-03-08 00:07:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,308
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26766259
Author URL: https://archiveofourown.org/users/Gement/pseuds/Gement
Summary: In which Batman is Bruce Wayne...'s slightly younger secret half-brother, and in which they like to shareeverything.[One-shot AU, because the Doublebat Twins were a kink prompt waiting to happen.]
Relationships: Batman & Bruce Wayne, Batman/Batman/OMC, Bruce Wayne/OMC
Series: Batman: Millennials in Love [5]
Series URL: https://archiveofourown.org/series/1636105
Comments: 17
Kudos: 27





	Gemini

**Author's Note:**

  * Inspired by [Light and Shadow](https://archiveofourown.org/works/23047042) by [Gement](https://archiveofourown.org/users/Gement/pseuds/Gement). 



> Because I am a stickler for accuracy: "Batman & Bruce Wayne" is a useful but wrong approximation. It's B and Bruce, and each is exactly as much Batman. One just spends more time in the suit, and the other in the cave. They're Batman. They just get twice as much done.
> 
> If you can roll with "Bruce has a boyfriend and a sex dungeon," then add in a bastard half-brother, you're good to go.

_The reveal (revised)_

Bruce Fucking Wayne. B's brother was Bruce Fucking Wayne, and they and their matching jawlines were both in Zach's _apartment_ , talking like this was a _reasonable way for two people to run their lives_ , and . . .

B rubbed his shoulders slowly. "Now, it's up to you, obviously. But historically speaking, once someone knows?" He put his mouth almost to Zach's ear. "We like to share _everything_."

Zach took stock. One of the richest men in the world sat in his armchair, body language carefully reserved but eyes hungry. Bruce Wayne's tailored shirt barely concealed shoulders and biceps almost as large as his brother's. "Yeah," Zach said. "I'm up for that."

B pulled both his arms back, catching his upper arms behind him and forcing his chest forward. Bruce walked over to the couch, unhurried, and kissed him. It was slow and deep and took forever. B's hands were almost bruising his arms.

Yeah. Zach was up for that.

* * *

_Two years later_

On the drive back to the manor, with the top down and the wind roaring in their ears, Bruce said, "Oubliette the rest of the day?" Just like that. Friendly, normal, one in the afternoon on a Saturday, did Zach want to disappear into the secret dungeon until . . . whenever they let him out.

Zach checked in with his body, his instincts, his slightly shaky hands. He watched the gray sky and the dingy scrub meadows, punctuated by the beginnings of the forest. "Yeah."

* * *

_Oubliette_

He took an hour to himself first. Washing up, taking a walk, settling himself. He returned to find Bruce in their bedroom, waiting for him with the wheeled box and the eyeless cowl. It was less romantic than being hauled around bodily, but also faster and a lot more comfortable. Bruce laced the hood tight around Zach's head, flattening his ears and hugging his throat. "Arms up, eyes up."

Zach reached his arms and turned his blind face toward the ceiling. Bruce spun him a dozen or so times clockwise, then counterclockwise a few more until Zach's feet went out from under him, completely out of touch with which way was up. Bruce tucked his bare body neatly into the padded crate. Muffled, disoriented, he was rolled away to the oubliette.

At the other end of the ride, he put his arms around Bruce's neck and shoulders to be carried to the bed. Bed was a data point. Cotton soft under Zach's grasping fingers but the curve of Bruce's clavicle bare against Zach's cheek: Bruce still wearing an undershirt, data point. Shoulders strapped to the backboard, with the memory foam under his spine to push his chest up, those were a data point. So were the really good padded restraints that covered inches of his forearms with no chance of leaving marks. Data point: arms drawn straight out to either side instead of stretched higher.

The strap low across his ribs drew tight. He took shallow breaths.

Arms straight out and the backboard to keep his torso really still meant no breaks to roll his shoulders. No struggle. Precision. He would stay pinned in that position until Bruce had finished. The bed instead of the padded table meant he would stay there after Bruce was done, too. B always wanted the bed.

Bruce tugged each of his ankles out to spread-eagled. Zach wondered if they'd ever take off the hood.

Just as the thought passed by, Bruce sat down beside him and unbuckled the hood's collar. He released Zach's face into soft, diffuse light. Black drapery kept the space around the bed formless anyway, but it didn't make much difference with Bruce's eyes drilling into him, devouring his attention. He rubbed Zach's cheekbones, nose, eyelids, scalp, all the distracting little itches that Zach couldn't reach for himself. He kissed Zach, and kept kissing.

Bruce really loved kissing. He devoted his whole body to it. Delicate, ravenous, wet, with teeth and without. Hands wrapping around Zach's skull and brushing his throat. He kissed Zach breathless, then kissed him more.

Zach knew this game. He relaxed into the push and pull of Bruce controlling his head. The rhythm was something close to hypnosis. He had to relax. Trust. Settle. He settled.

Bruce pulled on surgical gloves. The unmistakable smell of antiseptic filled the space. Oh god. He started wiping down Zach's chest. Zach kept his jaw loose and his breath slow as Bruce wiped down absolutely every inch of exposed skin from Zach's neck to his toes, always from his center line toward the edges. Zach's adrenaline surged with dread, but it balanced against the calm of inevitability. He wasn't going to ask to leave, and Bruce wasn't going to stop. Everything else was details.

There would be a lot of details.

Bruce uncapped one of the finest possible needles and slid it through the skin of Zach's chest, a couple inches up from the nipple. It barely stung. Three needles, side by side in tight parallel like the tines of a fork. Then three crossed perpendicular, dug in under the first set to pull the skin tighter. Zach hissed. Slow breaths.

Bruce touched his fingertip lightly to the crisscrossed endorphin button and waited as Zach's system flooded with giddy chemistry. Needles were a very, very quick high. When Zach was feeling no pain, or at least caring little for minor stab wounds, Bruce put a matching button on the other side. He kissed Zach again, but not using his hands. Those were in the land of pain and semi-sterile fields.

Bruce's hands were beautiful. Fingers long and nimble in milk-white gloves, pausing over his tray before selecting a scalpel. Not a classic steel scalpel, no. Obsidian scalpel, sharp as diamond and oh so fragile. Scientific supply places sold them. Bruce did not buy them there. Bruce knapped his own with equipment in the cave. Zach had watched once. Bruce's eyes were utterly focused then, as they were utterly focused when he drew the scalpel down the line of Zach's sternum, barely touching, not even stinging. Zach waited to breathe until the hand lifted; he had no other way to tell the stroke was finished.

He lifted his head to look at the pale pink scratch. Bruce wafted a breeze across Zach's skin with his hand, and the exposed nerves prickled, startled into reporting pain. Zach gasped, then breathed. He settled his head back on the bed. It would be easier if he didn't look.

Bruce traced designs across his chest and ribs. Long curves and straight lines and little hashes. Webs and lattices. He'd never drawn the bat. Tempting, but there was always the slight chance of scarring, no matter how many spot tests and how much care and antiseptic. No bats. Not where they could ever show.

Maybe someday they'd figure out where they could cut or burn or tattoo, somewhere that wouldn't be found, and then he could carry them with him, no matter what happened. Someday.

 _Thunk_. A dulled scalpel dropped into the prosaic red sharps bin. Bruce's mouth brushed across his cheeks and eyelids. "Deep breaths," he said.

Zach had been holding his breath or panting shallowly from his belly. A deep breath . . . He opened his eyes to focus on Bruce's serious, attentive stare. He inhaled and let his chest expand with it.

His skin split open everywhere and pain spilled out. "Ah," his throat said in a high whimper, "ah, ah, ah, ah." He'd tried being stoic before, being dignified, being a smartass until he couldn't anymore. All of it just hurt more and longer, not because of anything Bruce did. Tension made it worse. Surrender let him float.

He surrendered. He breathed and felt the web of his own skin tighten around each breath. Bruce smiled at him and kissed his forehead tenderly. "Chest breaths now."

Bruce didn't give him a chance for self-control to fail him. One gloved hand held his belly taut and still for each faint slice. Long, narrow diagonals like gills, exactly where B liked to grab his waist for handles. Zach's breath shook. The pain was spreading, radiating out to warn the rest of his body of danger. As if the warning would do any good.

When Bruce finished with that scalpel and touched his lips to Zach's sweating temple, Zach finally started crying. He couldn't cry very hard, because that would hurt more. He nuzzled at Bruce's face, trying for a few more seconds of relief. Bruce drank his tears, gentle and merciless. Then he put on fresh gloves and started tracing lines of fire along Zach's soft inner arms.

Everything hurt, only precise lines hurt, nothing hurt and Zach hovered far away. His limbs tugged at the cuffs. He heard his voice, crying out unsupervised. No words. Words were tension. Just float and feel the razor web tighten slowly along his arms and legs.

He felt moisture trickling down his ribs. Mostly sweat, he knew, but lifting his head to look would be tension. He wasn't dripping blood like a painting of a martyred saint. It just felt like it.

Bruce stopped at the cuffs. Insofar as Zach had attention for anything but the sizzle of his nerves, he was grateful. The time Bruce had put fine curlicues along his feet, even putting on socks had been excruciating for days; Zach had asked him not to do that one again. Bruce hadn't made any promises, because there were no promises in the oubliette except the right to leave, but he'd respected that line since.

There was no time in the oubliette, especially not when the literal knives were out, but Zach thought it had been a while. Maybe an hour. Maybe longer. Bruce cut slowly, with long pauses to consider his next stroke and to let Zach float.

He'd never done Zach's whole body before. Clothes would be a misery, but that was tomorrow's problem. And Bruce would be so careful with him for days, massaging strained muscles and rubbing down all the nearly invisible scratches with lotion and the terrible, terrible salve. Breakfast in bed and dinners lounging on the couch, Bruce absently ruffling Zach's scalp while he read or worked on the endless data analysis from his laptop instead of the cave, with Alfred pointedly ignoring the changes in routine.

It had been a while since a cut, maybe. Zach opened his eyes. Yes, Bruce sat at the edge of the bed, admiring his work and watching Zach's face. He smiled when he saw the open eyes. Zach blinked hazily.

"Perfect," Bruce said quietly. He kissed Zach's forehead, then pressed one gloved fingertip to an endorphin button. Zach didn't feel any effect, but his eyes closed out of habit.

The bed shifted. Liquid sloshed, tipping back and forth in its bottle. Zach squeezed his eyes more tightly closed and tried to brace himself.

Bruce stroked down his sternum with a gauze pad, cold and wet, and the first line lit up hot. Zach had assumed, the first time, that it was some medical-grade antiseptic, but no. Salt water. One line at a time, in exactly the order of the original cuts. Zach hissed breaths through his teeth and strained, his detachment gone. He held out for five lines before he started thrashing, four more until he started screaming and didn't stop.

Bruce went just as slowly with salt as with blades, washing Zach with meditative precision. As Zach began to wear out on screaming, he became aware of prickling unease. His eyes were closed, he was making a lot of noise, and there was absolutely no way he should be able to tell, but he could tell.

B was watching. Might have been watching the whole time, but he had shifted from lurking to looming. He was watching Zach, eating up his pain, and he wanted Zach to know it. He would get his turn next, and he wanted Zach to know it.

Zach was _acutely_ aware.

Almost done. Bruce ran hot-cold strokes along his left leg . . . his right . . . That was all the cuts. Bruce went back to his chest and drew out the dozen fine needles, one by one, completely unnoticed among the other sensations, then flooded those pinpricks with salt as well. Zach lay twitching, eyes glazed and unfocused at the invisible dark of the ceiling.

"Perfect." Bruce unstrapped Zach's shoulders and ribs from the backboard. The straps had dug in, leaving a few more angry lines. A hand slipped under his shoulder, loosening his sweating skin from the padding, and Bruce tugged the board out from under him, inch by inch past his head until his whole back lay on fresh, cool sheet.

Zach relaxed, relatively speaking. No more precision. Just Bruce's fingers rubbing little circles along the strap marks, making him hiss with discomfort-relief-pleasure as oxygen rushed back to those nerves. Bruce's face nuzzled his, cozy and close. He rolled his shoulders a little, easing the monotonous stretch, and Bruce helped by massaging and lifting the joints, careful not to touch any of the scratches.

Bruce wouldn't fuck him right away, or even jerk off. It would break the stillness of what he'd made. They'd fuck later, out in the world. In silence, Bruce wiped the tears and snot from his face, helped him blow his nose. Lifted his head to let him sip water from a straw. Kissed his eyelids. Laid a final hand on his forehead. Vanished.

The light through his eyelids dimmed to a faint glow. He opened his eyes.

B stood at the foot of the bed, half in shadow, naked. The curves and wiry fur and bulk of him were accentuated by the dim. He looked like a caveman. His cock stood up hard between his legs. He would not be precise.

Zach relaxed gratefully. Bruce was great, but he'd known B first. There was something easier about his raw sensuality when he shed the suit and the discipline and the only name that didn't feel like an alias anymore.

Once he had Zach's attention, B crawled onto the bed between his legs. He studied the pattern silently, then nodded. "Beautiful."

He dragged his fingers through the traces of blood on Zach's chest and stuck them in his mouth. It had just about given Zach a heart attack the first time they'd crossed that line. It was his _blood_ , and Zach still fucked around, and it had gotten in B's _mouth . . ._

B had looked at him blankly. _Everyone else's does_ , he had said.

B licked his fingers, then crawled further up, carefully placing his hands and knees to avoid touching Zach's splayed-out body yet. He grabbed Zach's hair to hold him still and kissed him.

Zach tasted pennies and the ocean as B ate out his mouth. He moaned. He gave himself to it, high as a kite and laid out to be ravaged.

Eventually B crawled back down, dragging his tongue down Zach's chest as he went.

"He'll tell you off for that," Zach mumbled. "Mouth's filthy."

"I'll live," B said, and licked Zach's cock. He prodded at Zach's asshole with dry, gloved fingers. "Nice."

"Mm." Zach had stretched and slicked himself in advance last time, in an attempt to be helpful. B hadn't been appreciative.

B liked this part, controlling the stretch. He unchained one of Zach's legs for easy access, which didn't stress out _too_ many cuts, and started with two fingertips. Usually reasonable, but beyond difficult when Zach's sphincters were locked up with pain. Batman didn't pay much attention to locks, except to enjoy picking them.

Slowly, first knuckles only, he pried Zach's ass open. After a minute of that, he unchained the other leg, got a condom on, and reversed his position on the bed; his thighs to either side of Zach's ears made a familiar space, dark and humid. He rested the head of his cock in Zach's mouth, hot breath on Zach's cock as he kept working away at the puzzle. He got two fingers moving freely and added another, never going deeper. His wrists under Zach's thighs made nice leg support, easier to relax.

Zach sucked slowly. He was utterly wrecked and wasn't expected to be good at it. He enjoyed the shape of B's fat cock in his mouth. He opened wider to breathe around it, since his nose was still clogged from crying; every time he did, B tugged his rim open to match.

B took his time, working up to two fingers from each hand and using them to spread Zach apart like a porn close-up. He kept going just a little faster than Zach could handle, just enough to make him squirm. B ignored the squirming, but he shifted his cock on Zach's tongue.

Zach was stretched way more than he needed for even the hardest fuck, but only right at the entrance, not even lubed an inch further in. That . . . was concerning. Or would have been concerning, if Zach had the focus for that kind of thing.

His cuts burned. His fingers prickled, a little numb. His head spun. B shot a plunger of lube up his ass, good enough for safety concerns, not that there was any doubt of that. Zach occupied himself with the warm, friendly gag in his mouth.

B lifted his hips, leaving Zach empty-mouthed and blinking in the light. He studied Zach from head to toe, pinched a cold hand with a disapproving look, and gave the wrist cuffs a little more slack. Zach opened and closed his hands to keep the circulation moving until he got a nod, then went back to floating.

Back at the foot of the bed, B hooked the ankle cuffs to each other, moving slowly to avoid jarring the cuts. Then he ducked his shoulders under Zach's linked ankles, head between them. His eyes and the set of his jaw were a warning. Zach held his breath.

B surged up to his knees, picking Zach up by the hips. Every line of pain woke up as Zach was pulled up to rest only on his calves and his aching shoulders. B shoved in so fast that Zach's first wail turned into a breathless grunt.

The head of B's cock was blunt and enormous and made way for itself with no room for argument. And then he held it there, perfectly still for a moment with his hips pressed hard against Zach's asscheeks, then almost all the way out, stretching the rim, in again like a punch. Almost out and in again. In again. In again.

It wasn't quick. A little slower than a second for each thrust, maybe. Like B's sluggish resting heart rate, or a slow drumbeat. Long enough for Zach to shift between the net of pain and the deep shock of getting pounded, over and over.

"I haven't timed myself in a while," B said in a low rasp. "How long do you think I can hold this? An hour? Three?" He didn't break pace.

Zach didn't say anything, just flexed his hands and fingers, straining against the cuffs as a balancing sensation. B wasn't talking to him particularly, and definitely didn't expect or need any answer. Zach would take it for an hour, or three, or however long B could go before his back got tired or he decided he wanted to come.

He took it. He groaned. His eyes stung with tears again, or maybe sweat. B's stroke settled down to something more deep and rolling, less thrust but more angle, still steady as a metronome, hips slapping his ass every second and a half.

Zach zoned out a little. He startled when B shifted his hands from Zach's hips to the gill slices on his waist.

"You going to take a nap?" B sounded amused. "Go ahead. I'll be here when you wake up."

Not with B's hands tight on those parallel slashes, he wasn't. Zach whimpered. B laughed under his breath. Time stretched, measured only in loud, slick thrusts and the endless shrieking of his nerves.

B shifted his angle and Zach gasped. B usually couldn't make him come untouched, but mostly because it took for-fucking-ever. Well, they had for-fucking-ever, so. He arched, ignoring the pain, working with the pain, focusing on the slow buildup of B rubbing up into him, jerking him off from the inside. He'd get there. Eventually. Whether he still had the energy to appreciate it or not.

Closer. Closer. Getting there. He could almost . . . Nearly . . .

B reached out and pressed his thumb to a spot on Zach's ribs. Pain crackled out along the lines that crossed there, intense enough that Zach twisted, trying to escape, escape everything. By the time B let him go, the build toward climax had slipped away.

"Amazing work," B said. "Really nice." He licked his thumb.

Zach would have sworn at him, but he didn't have the energy, and words were far away. He moaned. B started pushing him slowly up the orgasm hill again. Fucking hell.

B really might be taking three hours. Zach floated again, half-dreaming in exhaustion, burning inside and out, swimming in acid and fire and fucking and gentle touches and handsome bastards with a bat fetish. He floated almost to the surface again, desperate to gasp a full breath of pleasure, and B shoved him under again, his senses tangled and dragged down in the net of his own body.

"You're perfect," B said under his breath between strokes. "Perfect canvas. Perfect fuck. Perfect mouth. Perfect scream. Perfect sweat. Perfect struggle. Perfect body. To keep here. To use. When we want. How we want. Long as we want." He kept chanting, almost to himself, keeping the same rhythm but thrusting harder, sharper, yanking the body in his hands up and down.

The body on the bed moved where it was pulled, shoulders wrenched, cuts sizzling, ass burning, back and legs aching from the tension, throat sore, head dizzy, almost coming again, so close, so close, and maybe B would let it come this time, if he wanted to, if he wouldn't rather keep going for another fucking hour . . .

But B was getting impatient. He wanted to come too, and the body was being so good. It had taken everything they'd given it. It hadn't complained at all as it struggled and bled. They liked to make it feel good, too, not just tease it, and maybe, nearly . . . nearly . . .

B leaned down and forward, nose to nose, folding the body in half and planting the weight of his hands on its chest. "Come."

Zach screamed, body jerking, balls emptying with a hard clench. Pleasure was in there somewhere, in the pounding and the pain and his heartbeat thundering in his ears and his skin and low in his gut. Too much, too much, too much.

He lay crucified and screaming as B hammered him. B's face was red. Sweat dripped from his hair into Zach's eyes. Zach blinked and tried to keep them open anyway, to see the stripped expression on his face, nothing but sensation and effort, and then B arched back, easy, easy, bellowing with pleasure.

Zach lay where he was dropped, still in agony. The fun parts were over, he was sensitive as hell, there was _literal salt in his literal wounds_ , and he was very, very ready to see a room with a window soon.

B pulled a black pillowcase over Zach's head before uncuffing him. The box didn't sound fun and neither did a mile of jouncing around naked in the hallways, but the only way out was through, so he curled into B's bridal carry, skin against lacerated skin.

They only went a few dozen paces. Cold open hallway, then warm steam with echoes off tile, and B leaned down to ease him into an enormous tub and Bruce's arms. The heat hurt, but the water didn't sting as much as it should. Maybe he was just too tired to feel any more pain.

"Two eleven," Bruce said, and pulled the bag from Zach's head. The bathroom was lit by dim red lamps, easy on his dark-adapted eyes.

"Minutes?" B disappeared into the shower enclosure, a dark shadow against the frosted glass. The shower hissed to life.

Bruce snorted. "You're not _that_ good." He kept Zach leaning back against his chest so the cuts didn't have to touch anything. He ran a gentle hand across Zach's belly, more swishing the water against him than touching. It felt good.

Two hours, eleven minutes. Not quite a record, but close. Zach realized he was floating a little in the tub, his butt not quite settled between Bruce's thighs. Lifting his hand sounded like work, so he listed his head to the side, reaching his lips toward the water.

Bruce slid two fingers into his mouth instead. Salty, but not as much. "Normal saline," he said. "Point nine percent, exactly what your body expects." He kept washing, sluicing the extra salt away from every inch of Zach.

"Mmm," Zach said. He watched the shape of B through half-closed eyes, sitting on a bench in the shower, sprawled back under the hot water to enjoy his afterglow.

"Not to bait and switch," Bruce said, "but since we're right next door and can't let you wander off without the hood, we're effectively still in the pit." He poured water over Zach's shoulders. "And I have waited patiently for the second half of my turn while _someone_ took his sweet time, so you're not leaving this tub until I've fucked you in it."

Zach flopped his head back, leaning it against Bruce's jaw. "You are both complete bastards."

"No, just me," B said cheerfully from the shower. Call and response. Zach closed his eyes and let Bruce slosh normal saline through his hair.

**Author's Note:**

> That first image of B in the oubliette is a love letter to the title page of [The Return of Bruce Wayne #1](https://www.wired.com/images_blogs/underwire/2010/05/bmrbw_1_dylux-4-copy.jpg). Hng.
> 
> This is also sneakily fix-it fic for a _different_ Nolan+Bale movie, which I will not name for the sake of spoilers but will discuss freely in the comments.
> 
> If anyone else wants to play with the Doublebat Twins, you are _emphatically_ welcome to do so. (Drop a comment so I can go read it!) Directly inspired and requested by CallMyName. Beta thanks to [Internerdionality](https://archiveofourown.org/users/Internerdionality), [OkayAristotle](https://archiveofourown.org/users/OkayAristotle), and [shinetheway](https://archiveofourown.org/users/shinetheway).


End file.
